What is the greatest common factor of $9$ and $27$ ? Another way to say this is: $\operatorname{gcf}(9, 27) = {?}$
Explanation: The greatest common factor is the largest number that is a factor of both $9$ and $27$ The factors of $9$ are $1$ $3$ , and $9$ The factors of $27$ are $1$ $3$ $9$ , and $27$ Thus, the greatest common factor of $9$ and $27$ is $9$. $\operatorname{gcf}(9, 27) = 9$